Heat exchangers of this type are frequently used in process-engineering installations alongside a plurality of different installation components such as, for example, machines, containers, chemical reactors, steam generators, columns or pumps. A heat exchanger is in principle a pipe through which a product that is to be cooled or heated by the surrounding medium, which is called the auxiliary medium, flows. Factors determining the capacity of the heat exchanger include as large as possible a heat-exchange area and as large as possible a heat transfer coefficient. Certain requirements for the heat exchanger emerge from the materials used, for example, the type of product and auxiliary medium, the necessary cooling or heating capacity, the cooling procedure used, structural conditions or legal regulations, for example with regard to cleaning. Because of the different requirements, many different forms of heat exchangers are widespread, for example, direct-current and counter-current heat exchangers, tube-bundle-type heat exchangers or plate-type heat exchangers.
A major problem in the operation of heat exchangers is what is known as fouling. Here, fouling is a collective term for contamination of all kinds. Fouling changes the heat transfer coefficient between the auxiliary medium which serves as a cooling or heating medium and the product. The consequences of this are that more cooling medium or heating medium is required as auxiliary medium, that the operating costs rise and/or that in the extreme case the desired temperature of the product can no longer be set by the heat exchanger. If this extreme case occurs, an unscheduled shutdown of the process-engineering installation in which the heat exchanger is used can be caused as a result. A common remedial measure is therefore a regular shutdown of production for the maintenance and cleaning of heat exchangers. However, this increases operating costs and restricts the availability of the installation.